David Robson: Herb of the year - horseradish

The way horseradish got its name is a mystery, but you can grow the plant without too much trouble.

DAVID ROBSON

Think of a pink slab of prime beef. Think of shrimp cocktail. Think of a Bloody Mary. Think of a Passover Seder. Think of Dagwood Bumstead’s sandwiches.

Think of the common bond: horseradish, the International Herb Society’s 2011 Plant of the Year.

Horseradish is a love-it-or-hate-it condiment. Some people slather it on any sandwich. Others can’t stand the pungent taste, which can be bitter — especially if the horseradish is past prime.

The root is often mixed with mayonnaise or mustard. When grated horseradish is mixed with the former, it’s usually called horseradish sauce. Plain, grated horseradish is commonly called prepared horseradish.

The herb is different from most herbs. It doesn’t have the square stems and opposite leaves of basil, sage and most mints. The leaves, while edible, are not the main part that’s used. Eventually the plant flowers, but if harvested correctly, it seldom blooms.

The roots are the valued part, and they have been for millennia.

The derivation of the name is steeped in fancy detective footwork. The “radish” is definitely from the Latin “radix,” which means root.

The “horse” part is more convoluted. In Germany, the plant was known as sea radish, with the German word “meer” for sea. The genus is Armoracia, which is Latin for “by the sea.”

You can visualize a corruption of “meer” to “mare,” and then like a child playing free association, go from “mare” to “horse.” It’s all conjecture, but it makes for great cocktail party conversation.

Horseradish is a member of the Brassica family, which includes radish, broccoli, cabbage, cauliflower and turnips, each producing a cross-shaped flower if and when the plants finally bloom.

The Egyptians valued horseradish. So did the Greeks, who associated its value on par with gold. The Romans used the plant mainly for medicinal purposes, including bronchitis, urinary tract infections and sinus congestion, which is easy to understand because freshly ground horseradish can clear sinuses in a nanosecond.

There is evidence that horseradish was used on ingrown toenails, though this is far from a recommendation. Talk to your podiatrist.

Horseradish root has been used as an aphrodisiac much like ginseng. They both share a resemblance to the human body if you squint your eyes enough and have downed some fermented beverages.

Horseradish is a perennial, coming back year after year. The leaves are thick and leathery with a dark-green color. The leaves are bunched together and sit on a crown much like dandelion leaves. Leaves can reach 18 to 24 inches long and about 6 to 8 inches wide.

Roots are covered with a thick buff to brown bark that needs to be peeled before shredding or grinding the white flesh beneath.

Most roots are about 8 to 12 inches long and about an inch thick when harvested. Thinner roots are harder to peel and grind, while much thicker roots are woody.

Roughly 80 to 90 percent of the horseradish processed in the world is produced around Collinsville, Ill.

Most gardeners probably wouldn’t feature horseradish in the landscape. The plant probably would be relegated to the far corners of the yard or behind the garage.

You need a sunny location where horseradish can grow undisturbed for several years. It can grow in just about any soil, but if you want long, straight roots for easy peeling and grinding, add lots of organic matter to create a loose soil.

Work the soil to a 12-inch depth. Remove any rocks. Horseradish loves to spread just like mint, so contain it in a small patch.

Most horseradish is grown from small roots harvested around the main roots. Roots are planted in the early spring, with the finger-thick roots laid horizontally with the crown or thicker end tilted a little toward the surface.

Give the roots a thorough watering. Now comes the easy part. Ignore the plant until you’re ready to harvest. Commercial growers do some ridge planting, lifting and severing some of the new growth to get huge roots. While the same techniques can be modified for homeowners, it’s often too much work for as little horseradish as most homeowners will eventually use.

Too much fertilizer and water will result in lots of top growth and roots that may be too mild when ground. Mulching might keep weeds down, but once the roots get established, they often choke out other plants.

Roots can be harvested in the late fall after a frost (usually in mid-to-late October). Save some smaller roots in the refrigerator to plant the following spring. You can also harvest roots in early spring, before new growth starts. Then just replant some of the smaller roots.

David Robson is a specialist with the University of Illinois Extension. For more gardening information, go to www.extension.uiuc.edu/mg.